I-B-Quick its a possibility that you may have one of the older sets fitted to your mini, as the new sets dont have the bleed nipples screwed right into the alloy, and instead are screwed into a stainless threaded piece which is screwed into the calliper itself to stop the 'chewing' of the thread's.
Mini Sport were aware that they had problems with these in the past, these problems have now been rectified and i can assure you that the callipers produced now are to the highest standard's.
zeroasylum i think you have misunderstood what Mini Sport have said to yourself, the callipers have all been designed to use and run on standard Mini hubs and drive flanges (or the alloy hubs/flanges)
Thank you for the reply. Have just bought a set as looking at it all they are good value for money. Thanks for all the advice guys. will let you know how it goes.
Zeroasylum